seq_queue.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *   ALSA sequencer Timing queue handling
  4 *   Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
  5 *
  6 * MAJOR CHANGES
  7 *   Nov. 13, 1999	Takashi Iwai <iwai@ww.uni-erlangen.de>
  8 *     - Queues are allocated dynamically via ioctl.
  9 *     - When owner client is deleted, all owned queues are deleted, too.
 10 *     - Owner of unlocked queue is kept unmodified even if it is
 11 *	 manipulated by other clients.
 12 *     - Owner field in SET_QUEUE_OWNER ioctl must be identical with the
 13 *       caller client.  i.e. Changing owner to a third client is not
 14 *       allowed.
 15 *
 16 *  Aug. 30, 2000	Takashi Iwai
 17 *     - Queues are managed in static array again, but with better way.
 18 *       The API itself is identical.
 19 *     - The queue is locked when struct snd_seq_queue pointer is returned via
 20 *       queueptr().  This pointer *MUST* be released afterward by
 21 *       queuefree(ptr).
 22 *     - Addition of experimental sync support.
 23 */
 24
 25#include <linux/init.h>
 26#include <linux/slab.h>
 27#include <sound/core.h>
 28
 29#include "seq_memory.h"
 30#include "seq_queue.h"
 31#include "seq_clientmgr.h"
 32#include "seq_fifo.h"
 33#include "seq_timer.h"
 34#include "seq_info.h"
 35
 36/* list of allocated queues */
 37static struct snd_seq_queue *queue_list[SNDRV_SEQ_MAX_QUEUES];
 38static DEFINE_SPINLOCK(queue_list_lock);
 39/* number of queues allocated */
 40static int num_queues;
 41
 42int snd_seq_queue_get_cur_queues(void)
 43{
 44	return num_queues;
 45}
 46
 47/*----------------------------------------------------------------*/
 48
 49/* assign queue id and insert to list */
 50static int queue_list_add(struct snd_seq_queue *q)
 51{
 52	int i;
 53
 54	guard(spinlock_irqsave)(&queue_list_lock);
 55	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
 56		if (! queue_list[i]) {
 57			queue_list[i] = q;
 58			q->queue = i;
 59			num_queues++;
 60			return i;
 61		}
 62	}
 63	return -1;
 64}
 65
 66static struct snd_seq_queue *queue_list_remove(int id, int client)
 67{
 68	struct snd_seq_queue *q;
 69
 70	guard(spinlock_irqsave)(&queue_list_lock);
 71	q = queue_list[id];
 72	if (q) {
 73		guard(spinlock)(&q->owner_lock);
 74		if (q->owner == client) {
 75			/* found */
 76			q->klocked = 1;
 77			queue_list[id] = NULL;
 78			num_queues--;
 79			return q;
 80		}
 81	}
 82	return NULL;
 83}
 84
 85/*----------------------------------------------------------------*/
 86
 87/* create new queue (constructor) */
 88static struct snd_seq_queue *queue_new(int owner, int locked)
 89{
 90	struct snd_seq_queue *q;
 91
 92	q = kzalloc(sizeof(*q), GFP_KERNEL);
 93	if (!q)
 94		return NULL;
 95
 96	spin_lock_init(&q->owner_lock);
 97	spin_lock_init(&q->check_lock);
 98	mutex_init(&q->timer_mutex);
 99	snd_use_lock_init(&q->use_lock);
100	q->queue = -1;
101
102	q->tickq = snd_seq_prioq_new();
103	q->timeq = snd_seq_prioq_new();
104	q->timer = snd_seq_timer_new();
105	if (q->tickq == NULL || q->timeq == NULL || q->timer == NULL) {
106		snd_seq_prioq_delete(&q->tickq);
107		snd_seq_prioq_delete(&q->timeq);
108		snd_seq_timer_delete(&q->timer);
109		kfree(q);
110		return NULL;
111	}
112
113	q->owner = owner;
114	q->locked = locked;
115	q->klocked = 0;
116
117	return q;
118}
119
120/* delete queue (destructor) */
121static void queue_delete(struct snd_seq_queue *q)
122{
123	/* stop and release the timer */
124	mutex_lock(&q->timer_mutex);
125	snd_seq_timer_stop(q->timer);
126	snd_seq_timer_close(q);
127	mutex_unlock(&q->timer_mutex);
128	/* wait until access free */
129	snd_use_lock_sync(&q->use_lock);
130	/* release resources... */
131	snd_seq_prioq_delete(&q->tickq);
132	snd_seq_prioq_delete(&q->timeq);
133	snd_seq_timer_delete(&q->timer);
134
135	kfree(q);
136}
137
138
139/*----------------------------------------------------------------*/
140
141/* delete all existing queues */
142void snd_seq_queues_delete(void)
143{
144	int i;
145
146	/* clear list */
147	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
148		if (queue_list[i])
149			queue_delete(queue_list[i]);
150	}
151}
152
153static void queue_use(struct snd_seq_queue *queue, int client, int use);
154
155/* allocate a new queue -
156 * return pointer to new queue or ERR_PTR(-errno) for error
157 * The new queue's use_lock is set to 1. It is the caller's responsibility to
158 * call snd_use_lock_free(&q->use_lock).
159 */
160struct snd_seq_queue *snd_seq_queue_alloc(int client, int locked, unsigned int info_flags)
161{
162	struct snd_seq_queue *q;
163
164	q = queue_new(client, locked);
165	if (q == NULL)
166		return ERR_PTR(-ENOMEM);
167	q->info_flags = info_flags;
168	queue_use(q, client, 1);
169	snd_use_lock_use(&q->use_lock);
170	if (queue_list_add(q) < 0) {
171		snd_use_lock_free(&q->use_lock);
172		queue_delete(q);
173		return ERR_PTR(-ENOMEM);
174	}
175	return q;
176}
177
178/* delete a queue - queue must be owned by the client */
179int snd_seq_queue_delete(int client, int queueid)
180{
181	struct snd_seq_queue *q;
182
183	if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
184		return -EINVAL;
185	q = queue_list_remove(queueid, client);
186	if (q == NULL)
187		return -EINVAL;
188	queue_delete(q);
189
190	return 0;
191}
192
193
194/* return pointer to queue structure for specified id */
195struct snd_seq_queue *queueptr(int queueid)
196{
197	struct snd_seq_queue *q;
198
199	if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
200		return NULL;
201	guard(spinlock_irqsave)(&queue_list_lock);
202	q = queue_list[queueid];
203	if (q)
204		snd_use_lock_use(&q->use_lock);
205	return q;
206}
207
208/* return the (first) queue matching with the specified name */
209struct snd_seq_queue *snd_seq_queue_find_name(char *name)
210{
211	int i;
212
213	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
214		struct snd_seq_queue *q __free(snd_seq_queue) =
215			queueptr(i);
216
217		if (q) {
218			if (strncmp(q->name, name, sizeof(q->name)) == 0)
219				return no_free_ptr(q);
220		}
221	}
222	return NULL;
223}
224
225
226/* -------------------------------------------------------- */
227
228#define MAX_CELL_PROCESSES_IN_QUEUE	1000
229
230void snd_seq_check_queue(struct snd_seq_queue *q, int atomic, int hop)
231{
232	struct snd_seq_event_cell *cell;
233	snd_seq_tick_time_t cur_tick;
234	snd_seq_real_time_t cur_time;
235	int processed = 0;
236
237	if (q == NULL)
238		return;
239
240	/* make this function non-reentrant */
241	scoped_guard(spinlock_irqsave, &q->check_lock) {
242		if (q->check_blocked) {
243			q->check_again = 1;
244			return;	/* other thread is already checking queues */
245		}
246		q->check_blocked = 1;
247	}
248
249      __again:
250	/* Process tick queue... */
251	cur_tick = snd_seq_timer_get_cur_tick(q->timer);
252	for (;;) {
253		cell = snd_seq_prioq_cell_out(q->tickq, &cur_tick);
254		if (!cell)
255			break;
256		snd_seq_dispatch_event(cell, atomic, hop);
257		if (++processed >= MAX_CELL_PROCESSES_IN_QUEUE)
258			goto out; /* the rest processed at the next batch */
259	}
260
261	/* Process time queue... */
262	cur_time = snd_seq_timer_get_cur_time(q->timer, false);
263	for (;;) {
264		cell = snd_seq_prioq_cell_out(q->timeq, &cur_time);
265		if (!cell)
266			break;
267		snd_seq_dispatch_event(cell, atomic, hop);
268		if (++processed >= MAX_CELL_PROCESSES_IN_QUEUE)
269			goto out; /* the rest processed at the next batch */
270	}
271
272 out:
273	/* free lock */
274	scoped_guard(spinlock_irqsave, &q->check_lock) {
275		if (q->check_again) {
276			q->check_again = 0;
277			if (processed < MAX_CELL_PROCESSES_IN_QUEUE)
278				goto __again;
279		}
280		q->check_blocked = 0;
281	}
282}
283
284
285/* enqueue a event to singe queue */
286int snd_seq_enqueue_event(struct snd_seq_event_cell *cell, int atomic, int hop)
287{
288	int dest, err;
289
290	if (snd_BUG_ON(!cell))
291		return -EINVAL;
292	dest = cell->event.queue;	/* destination queue */
293
294	struct snd_seq_queue *q __free(snd_seq_queue) =
295		queueptr(dest);
296	if (q == NULL)
297		return -EINVAL;
298	/* handle relative time stamps, convert them into absolute */
299	if ((cell->event.flags & SNDRV_SEQ_TIME_MODE_MASK) == SNDRV_SEQ_TIME_MODE_REL) {
300		switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
301		case SNDRV_SEQ_TIME_STAMP_TICK:
302			cell->event.time.tick += q->timer->tick.cur_tick;
303			break;
304
305		case SNDRV_SEQ_TIME_STAMP_REAL:
306			snd_seq_inc_real_time(&cell->event.time.time,
307					      &q->timer->cur_time);
308			break;
309		}
310		cell->event.flags &= ~SNDRV_SEQ_TIME_MODE_MASK;
311		cell->event.flags |= SNDRV_SEQ_TIME_MODE_ABS;
312	}
313	/* enqueue event in the real-time or midi queue */
314	switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
315	case SNDRV_SEQ_TIME_STAMP_TICK:
316		err = snd_seq_prioq_cell_in(q->tickq, cell);
317		break;
318
319	case SNDRV_SEQ_TIME_STAMP_REAL:
320	default:
321		err = snd_seq_prioq_cell_in(q->timeq, cell);
322		break;
323	}
324
325	if (err < 0)
326		return err;
327
328	/* trigger dispatching */
329	snd_seq_check_queue(q, atomic, hop);
330
331	return 0;
332}
333
334
335/*----------------------------------------------------------------*/
336
337static inline int check_access(struct snd_seq_queue *q, int client)
338{
339	return (q->owner == client) || (!q->locked && !q->klocked);
340}
341
342/* check if the client has permission to modify queue parameters.
343 * if it does, lock the queue
344 */
345static int queue_access_lock(struct snd_seq_queue *q, int client)
346{
347	int access_ok;
348	
349	guard(spinlock_irqsave)(&q->owner_lock);
350	access_ok = check_access(q, client);
351	if (access_ok)
352		q->klocked = 1;
353	return access_ok;
354}
355
356/* unlock the queue */
357static inline void queue_access_unlock(struct snd_seq_queue *q)
358{
359	guard(spinlock_irqsave)(&q->owner_lock);
360	q->klocked = 0;
361}
362
363/* exported - only checking permission */
364int snd_seq_queue_check_access(int queueid, int client)
365{
366	struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);
367
368	if (! q)
369		return 0;
370	guard(spinlock_irqsave)(&q->owner_lock);
371	return check_access(q, client);
372}
373
374/*----------------------------------------------------------------*/
375
376/*
377 * change queue's owner and permission
378 */
379int snd_seq_queue_set_owner(int queueid, int client, int locked)
380{
381	struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);
382
383	if (q == NULL)
384		return -EINVAL;
385
386	if (!queue_access_lock(q, client))
387		return -EPERM;
388
389	scoped_guard(spinlock_irqsave, &q->owner_lock) {
390		q->locked = locked ? 1 : 0;
391		q->owner = client;
392	}
393	queue_access_unlock(q);
394
395	return 0;
396}
397
398
399/*----------------------------------------------------------------*/
400
401/* open timer -
402 * q->use mutex should be down before calling this function to avoid
403 * confliction with snd_seq_queue_use()
404 */
405int snd_seq_queue_timer_open(int queueid)
406{
407	int result = 0;
408	struct snd_seq_timer *tmr;
409	struct snd_seq_queue *queue __free(snd_seq_queue) =
410		queueptr(queueid);
411
412	if (queue == NULL)
413		return -EINVAL;
414	tmr = queue->timer;
415	result = snd_seq_timer_open(queue);
416	if (result < 0) {
417		snd_seq_timer_defaults(tmr);
418		result = snd_seq_timer_open(queue);
419	}
420	return result;
421}
422
423/* close timer -
424 * q->use mutex should be down before calling this function
425 */
426int snd_seq_queue_timer_close(int queueid)
427{
428	int result = 0;
429	struct snd_seq_queue *queue __free(snd_seq_queue) =
430		queueptr(queueid);
431
432	if (queue == NULL)
433		return -EINVAL;
434	snd_seq_timer_close(queue);
435	return result;
436}
437
438/* change queue tempo and ppq */
439int snd_seq_queue_timer_set_tempo(int queueid, int client,
440				  struct snd_seq_queue_tempo *info)
441{
442	struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);
443	int result;
444
445	if (q == NULL)
446		return -EINVAL;
447	if (!queue_access_lock(q, client))
448		return -EPERM;
449
450	result = snd_seq_timer_set_tempo_ppq(q->timer, info->tempo, info->ppq,
451					     info->tempo_base);
452	if (result >= 0 && info->skew_base > 0)
453		result = snd_seq_timer_set_skew(q->timer, info->skew_value,
454						info->skew_base);
455	queue_access_unlock(q);
456	return result;
457}
458
459/* use or unuse this queue */
460static void queue_use(struct snd_seq_queue *queue, int client, int use)
461{
462	if (use) {
463		if (!test_and_set_bit(client, queue->clients_bitmap))
464			queue->clients++;
465	} else {
466		if (test_and_clear_bit(client, queue->clients_bitmap))
467			queue->clients--;
468	}
469	if (queue->clients) {
470		if (use && queue->clients == 1)
471			snd_seq_timer_defaults(queue->timer);
472		snd_seq_timer_open(queue);
473	} else {
474		snd_seq_timer_close(queue);
475	}
476}
477
478/* use or unuse this queue -
479 * if it is the first client, starts the timer.
480 * if it is not longer used by any clients, stop the timer.
481 */
482int snd_seq_queue_use(int queueid, int client, int use)
483{
484	struct snd_seq_queue *queue __free(snd_seq_queue) =
485		queueptr(queueid);
486
487	if (queue == NULL)
488		return -EINVAL;
489	guard(mutex)(&queue->timer_mutex);
490	queue_use(queue, client, use);
491	return 0;
492}
493
494/*
495 * check if queue is used by the client
496 * return negative value if the queue is invalid.
497 * return 0 if not used, 1 if used.
498 */
499int snd_seq_queue_is_used(int queueid, int client)
500{
501	struct snd_seq_queue *q __free(snd_seq_queue) =
502		queueptr(queueid);
503
504	if (q == NULL)
505		return -EINVAL; /* invalid queue */
506	return test_bit(client, q->clients_bitmap) ? 1 : 0;
507}
508
509
510/*----------------------------------------------------------------*/
511
512/* final stage notification -
513 * remove cells for no longer exist client (for non-owned queue)
514 * or delete this queue (for owned queue)
515 */
516void snd_seq_queue_client_leave(int client)
517{
518	int i;
519
520	/* delete own queues from queue list */
521	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
522		struct snd_seq_queue *q = queue_list_remove(i, client);
523		if (q)
524			queue_delete(q);
525	}
526
527	/* remove cells from existing queues -
528	 * they are not owned by this client
529	 */
530	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
531		struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(i);
532		if (!q)
533			continue;
534		if (test_bit(client, q->clients_bitmap)) {
535			snd_seq_prioq_leave(q->tickq, client, 0);
536			snd_seq_prioq_leave(q->timeq, client, 0);
537			snd_seq_queue_use(q->queue, client, 0);
538		}
539	}
540}
541
542
543
544/*----------------------------------------------------------------*/
545
546/* remove cells based on flush criteria */
547void snd_seq_queue_remove_cells(int client, struct snd_seq_remove_events *info)
548{
549	int i;
550
551	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
552		struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(i);
553		if (!q)
554			continue;
555		if (test_bit(client, q->clients_bitmap) &&
556		    (! (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) ||
557		     q->queue == info->queue)) {
558			snd_seq_prioq_remove_events(q->tickq, client, info);
559			snd_seq_prioq_remove_events(q->timeq, client, info);
560		}
561	}
562}
563
564/*----------------------------------------------------------------*/
565
566/*
567 * send events to all subscribed ports
568 */
569static void queue_broadcast_event(struct snd_seq_queue *q, struct snd_seq_event *ev,
570				  int atomic, int hop)
571{
572	struct snd_seq_event sev;
573
574	sev = *ev;
575	
576	sev.flags = SNDRV_SEQ_TIME_STAMP_TICK|SNDRV_SEQ_TIME_MODE_ABS;
577	sev.time.tick = q->timer->tick.cur_tick;
578	sev.queue = q->queue;
579	sev.data.queue.queue = q->queue;
580
581	/* broadcast events from Timer port */
582	sev.source.client = SNDRV_SEQ_CLIENT_SYSTEM;
583	sev.source.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
584	sev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
585	snd_seq_kernel_client_dispatch(SNDRV_SEQ_CLIENT_SYSTEM, &sev, atomic, hop);
586}
587
588/*
589 * process a received queue-control event.
590 * this function is exported for seq_sync.c.
591 */
592static void snd_seq_queue_process_event(struct snd_seq_queue *q,
593					struct snd_seq_event *ev,
594					int atomic, int hop)
595{
596	switch (ev->type) {
597	case SNDRV_SEQ_EVENT_START:
598		snd_seq_prioq_leave(q->tickq, ev->source.client, 1);
599		snd_seq_prioq_leave(q->timeq, ev->source.client, 1);
600		if (! snd_seq_timer_start(q->timer))
601			queue_broadcast_event(q, ev, atomic, hop);
602		break;
603
604	case SNDRV_SEQ_EVENT_CONTINUE:
605		if (! snd_seq_timer_continue(q->timer))
606			queue_broadcast_event(q, ev, atomic, hop);
607		break;
608
609	case SNDRV_SEQ_EVENT_STOP:
610		snd_seq_timer_stop(q->timer);
611		queue_broadcast_event(q, ev, atomic, hop);
612		break;
613
614	case SNDRV_SEQ_EVENT_TEMPO:
615		snd_seq_timer_set_tempo(q->timer, ev->data.queue.param.value);
616		queue_broadcast_event(q, ev, atomic, hop);
617		break;
618
619	case SNDRV_SEQ_EVENT_SETPOS_TICK:
620		if (snd_seq_timer_set_position_tick(q->timer, ev->data.queue.param.time.tick) == 0) {
621			queue_broadcast_event(q, ev, atomic, hop);
622		}
623		break;
624
625	case SNDRV_SEQ_EVENT_SETPOS_TIME:
626		if (snd_seq_timer_set_position_time(q->timer, ev->data.queue.param.time.time) == 0) {
627			queue_broadcast_event(q, ev, atomic, hop);
628		}
629		break;
630	case SNDRV_SEQ_EVENT_QUEUE_SKEW:
631		if (snd_seq_timer_set_skew(q->timer,
632					   ev->data.queue.param.skew.value,
633					   ev->data.queue.param.skew.base) == 0) {
634			queue_broadcast_event(q, ev, atomic, hop);
635		}
636		break;
637	}
638}
639
640
641/*
642 * Queue control via timer control port:
643 * this function is exported as a callback of timer port.
644 */
645int snd_seq_control_queue(struct snd_seq_event *ev, int atomic, int hop)
646{
647	if (snd_BUG_ON(!ev))
648		return -EINVAL;
649
650	struct snd_seq_queue *q __free(snd_seq_queue) =
651		queueptr(ev->data.queue.queue);
652
653	if (q == NULL)
654		return -EINVAL;
655
656	if (!queue_access_lock(q, ev->source.client))
657		return -EPERM;
658
659	snd_seq_queue_process_event(q, ev, atomic, hop);
660
661	queue_access_unlock(q);
662	return 0;
663}
664
665
666/*----------------------------------------------------------------*/
667
668#ifdef CONFIG_SND_PROC_FS
669/* exported to seq_info.c */
670void snd_seq_info_queues_read(struct snd_info_entry *entry, 
671			      struct snd_info_buffer *buffer)
672{
673	int i, bpm;
674	struct snd_seq_timer *tmr;
675	bool locked;
676	int owner;
677
678	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
679		struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(i);
680		if (!q)
681			continue;
682
683		tmr = q->timer;
684		if (tmr->tempo)
685			bpm = (60000 * tmr->tempo_base) / tmr->tempo;
686		else
687			bpm = 0;
688
689		scoped_guard(spinlock_irq, &q->owner_lock) {
690			locked = q->locked;
691			owner = q->owner;
692		}
693
694		snd_iprintf(buffer, "queue %d: [%s]\n", q->queue, q->name);
695		snd_iprintf(buffer, "owned by client    : %d\n", owner);
696		snd_iprintf(buffer, "lock status        : %s\n", locked ? "Locked" : "Free");
697		snd_iprintf(buffer, "queued time events : %d\n", snd_seq_prioq_avail(q->timeq));
698		snd_iprintf(buffer, "queued tick events : %d\n", snd_seq_prioq_avail(q->tickq));
699		snd_iprintf(buffer, "timer state        : %s\n", tmr->running ? "Running" : "Stopped");
700		snd_iprintf(buffer, "timer PPQ          : %d\n", tmr->ppq);
701		snd_iprintf(buffer, "current tempo      : %d\n", tmr->tempo);
702		snd_iprintf(buffer, "tempo base         : %d ns\n", tmr->tempo_base);
703		snd_iprintf(buffer, "current BPM        : %d\n", bpm);
704		snd_iprintf(buffer, "current time       : %d.%09d s\n", tmr->cur_time.tv_sec, tmr->cur_time.tv_nsec);
705		snd_iprintf(buffer, "current tick       : %d\n", tmr->tick.cur_tick);
706		snd_iprintf(buffer, "\n");
707	}
708}
709#endif /* CONFIG_SND_PROC_FS */
710